NO. 7 MUSCULATURE OF COLEOPTERA DORSEY II 



12, is well developed. The dorsal dilator muscles of the cihariuin, 5, 

 6, and y, are essentially the same as those in Harpalus. 



For the larval forms in this superfamily, Aniara sp. and Galerita 

 sp. were studied. In Amara (figs. 20, 21, 22) the levator muscle of 

 the labial palpus, 24 (fig. 22), is strong and the dorsal and ventral 

 muscles of the labium, 20 and 21 respectively, are large. The dorsal 

 dilator muscles of the cibarium, 5, 6, and 7 (figs. 21, 22), are well 

 developed. The pharynx is small ; the dorsal dilator muscle of the 

 pliarynx, 11, is absent. Bar Y extends posteriorly along the sides of 

 the cibarium and is connected with the one on the opposite side by a 

 long, subpharyngeal, sclerotized area. In Galerita the dorsal and 

 ventral muscles of the labium, 20 and 21 respectively, are similar to 

 those in Amara. The dorsal dilator muscles of the cibarium, 5, 6, and 

 y, are grouped together to form a massive unit of muscle fibers. The 

 muscle of hypo pharyngeal bar Y , 10, is similar to that of Amara. 



IV. GYRINOIDEA 



The adults studied in this superfamily are Dineutes discolor Aube 

 and D. vittatus (Germ.), Gyrinidae. In D. discolor (figs. 23, 24, 25) 

 the labral muscles are absent. The dorsal dilator muscles of the 

 cibarium, 5, 6, and 7, the dorsal dilator mMScle of the anterior region 

 of the pharynx, p (fig. 24), the muscle of hypo pharyngeal bar Y, 10 

 (fig. 23), and the compressor muscle group of the cibarium, 12 (fig. 

 24), are all similar to those in Harpalus. The dorsal dilator muscle 

 of the pharynx, 11, is absent. Bar Y is also continuous with a sub- 

 pharyngeal support. There is an apodeme originating in the anterior 

 gular region essentially the same as the one in Harpalus; however, 

 only the dorsal and ventral muscles of the labimn, 20 and 21 respec- 

 tively (fig. 23), arise on it. The muscle of the hypopharynx, ip 

 (figs. 23, 25), arises by means of a T-shaped tendon, the lateral arms 

 of which originate on the walls of the gular suture. The musculature 

 of D. vittatus is practically the same as that in D. discolor. 



The larvae used for study are Dineutes sp. (figs. 26, 27, 28). The 

 dorsal dilator muscles of the cibarium, 5, 6, and 7, and the muscle 

 of hypopharyngeal bar Y, 10 (figs. 26, 28), are similar to those of 

 the larva of Amara sp. ; they are proportionately much more massive. 

 The dorsal dilator muscle of the pharynx, 11, is present and the com- 

 pressor m>uscle group of the cibarium, 12, is either absent or so poorly 

 developed that it is not noticeable. The labial muscles are essentially 

 the same as those of Amara with some variation as to shape. The 

 muscle of the prementuni, 22 (figs. 27, 28), is present in Dineutes. 



